Guard ring design enabling in-line testing of silicon bridges for semiconductor packages

ABSTRACT

Guard ring designs enabling in-line testing of silicon bridges for semiconductor packages, and the resulting silicon bridges and semiconductor packages, are described. In an example, a semiconductor structure includes a substrate having an insulating layer disposed thereon. A metallization structure is disposed on the insulating layer. The metallization structure includes conductive routing disposed in a dielectric material stack. The semiconductor structure also includes a first metal guard ring disposed in the dielectric material stack and surrounding the conductive routing. The first metal guard ring includes a plurality of individual guard ring segments. The semiconductor structure also includes a second metal guard ring disposed in the dielectric material stack and surrounding the first metal guard ring. Electrical testing features are disposed in the dielectric material stack, between the first metal guard ring and the second metal guard ring.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a U.S. National Phase Application under 35U.S.C. § 371 of International Application No. PCT/US2015/058072, filedOct. 29, 2015, entitled “GUARD RING DESIGN ENABLING IN-LINE TESTING OFSILICON BRIDGES FOR SEMICONDUCTOR PACKAGES,” which designates the UnitedStates of America, the entire disclosure of which is hereby incorporatedby reference in its entirety and for all purposes.

TECHNICAL FIELD

Embodiments of the invention are in the field of semiconductor packagesand, in particular, guard ring designs enabling in-line testing ofsilicon bridges for semiconductor packages and the resulting siliconbridges and semiconductor packages.

BACKGROUND

Today's consumer electronics market frequently demands complex functionsrequiring very intricate circuitry. Scaling to smaller and smallerfundamental building blocks, e.g. transistors, has enabled theincorporation of even more intricate circuitry on a single die with eachprogressive generation. Semiconductor packages are used for protectingan integrated circuit (IC) chip or die, and also to provide the die withan electrical interface to external circuitry. With the increasingdemand for smaller electronic devices, semiconductor packages aredesigned to be even more compact and must support larger circuitdensity. Furthermore, the demand for higher performance devices resultsin a need for an improved semiconductor package that enables a thinpackaging profile and low overall warpage compatible with subsequentassembly processing.

C4 solder ball connections have been used for many years to provide flipchip interconnections between semiconductor devices and substrates. Aflip chip or Controlled Collapse Chip Connection (C4) is a type ofmounting used for semiconductor devices, such as integrated circuit (IC)chips, MEMS or components, which utilizes solder bumps instead of wirebonds. The solder bumps are deposited on the C4 pads, located on the topside of the substrate package. In order to mount the semiconductordevice to the substrate, it is flipped over—the active side facing downon the mounting area. The solder bumps are used to connect thesemiconductor device directly to the substrate.

Processing a flip chip is similar to conventional IC fabrication, with afew additional steps. Near the end of the manufacturing process, theattachment pads are metalized to make them more receptive to solder.This typically consists of several treatments. A small dot of solder isthen deposited on each metalized pad. The chips are then cut out of thewafer as normal. To attach the flip chip into a circuit, the chip isinverted to bring the solder dots down onto connectors on the underlyingelectronics or circuit board. The solder is then re-melted to produce anelectrical connection, typically using an ultrasonic or alternativelyreflow solder process. This also leaves a small space between the chip'scircuitry and the underlying mounting. In most cases anelectrically-insulating adhesive is then “underfilled” to provide astronger mechanical connection, provide a heat bridge, and to ensure thesolder joints are not stressed due to differential heating of the chipand the rest of the system.

Newer packaging and die-to-die interconnect approaches, such as throughsilicon via (TSV), silicon interposers and silicon bridges, are gainingmuch attention from designers for the realization of high performanceMulti-Chip Module (MCM) and System in Package (SiP). However, additionalimprovements are needed for such newer packaging regimes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a cross-sectional view of a semiconductor packagehaving an Embedded Multi-Die Interconnection Bridge (EMIB) connectingtwo dies, in accordance with an embodiment of the present invention.

FIG. 1B illustrates a plan view showing the bump arrays of the first andsecond dies of FIG. 1A, in accordance with an embodiment of the presentinvention.

FIG. 2 illustrates a plan view of a portion of a silicon wafer having aplurality of silicon bridge dies fabricated thereon, in accordance withan embodiment of the present invention.

FIG. 3 illustrates a magnified layout for a dual guard ring design ofFIG. 2 highlighting test structures fabricated within dual guard ringstructure, in accordance with an embodiment of the present invention.

FIG. 4 illustrates a first implementation of a dual guard ring designenabling in-line testing of silicon bridge dies, in accordance with anembodiment of the present invention.

FIG. 5 illustrates a second implementation of a dual guard ring designenabling in-line testing of silicon bridge dies, in accordance with anembodiment of the present invention.

FIG. 6 illustrates a plan view of a portion of a silicon wafer from FIG.2 highlighting artifacts of implementations described herein, inaccordance with an embodiment of the present invention.

FIG. 7 illustrates a cross-sectional view of a possible E-test routinglayout for a silicon bridge die, in accordance with an embodiment of thepresent invention.

FIG. 8 is a schematic layout of an E-test spline for a silicon bridgedie, in accordance with an embodiment of the present invention.

FIG. 9 illustrates a cross-sectional view of a guard ring of a dualguard ring structure, in accordance with an embodiment of the presentinvention.

FIG. 10 illustrates a cross-sectional view of a dual guard ringstructure, in accordance with an embodiment of the present invention.

FIG. 11 illustrates a cross-sectional view of a semiconductor packageincluding multiple die coupled with an Embedded Multi-DieInterconnection Bridge (EMIB), in accordance with an embodiment of thepresent invention.

FIG. 12 illustrates a plan view of a package layout for co-packaged highperformance computing (HPC) die and high bandwidth memory (HBM) layout,in accordance with an embodiment of the present invention.

FIG. 13 is a schematic of a computer system, in accordance with anembodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Guard ring designs enabling in-line testing of silicon bridges forsemiconductor packages, and the resulting silicon bridges andsemiconductor packages, are described. In the following description,numerous specific details are set forth, such as packaging andinterconnect architectures, in order to provide a thorough understandingof embodiments of the present invention. It will be apparent to oneskilled in the art that embodiments of the present invention may bepracticed without these specific details. In other instances, well-knownfeatures, such as specific semiconductor fabrication processes, are notdescribed in detail in order to not unnecessarily obscure embodiments ofthe present invention. Furthermore, it is to be understood that thevarious embodiments shown in the Figures are illustrativerepresentations and are not necessarily drawn to scale.

One or more embodiments described herein are directed to guard ringdesigns for silicon (Si) bridges to enable in-line testing. Applicationsmay be particularly useful for so-called 2.5D packaging designs. As usedthroughout the term “silicon bridge” is used to refer to a die providingrouting for two or more device dies. The term “Embedded Multi-DieInterconnection Bridge (EMIB)” refers to the inclusion of such a siliconbridge die in a package substrate, or the resulting package. Embodimentsmay be implemented to solve issues surrounding detecting cross layerleakage in the Embedded Multi-Die Interconnection Bridge (EMIB) siliconusing fab (factory) inline E-test pads. It is to be appreciated thatcross layer leakage is difficult to detect using standard defectmetrology and can often only be detected at Sort operation. However, forthe fine pad pitches targeted by EMIB, the Sort technology oftendevelops along with the other aspects of the process and availability ofa Sort card for the development test chips or the first few lots of thelead product can be a challenge. In such scenarios, inline E-testcapability can be used to provide coverage to detect such fail modes.

To provide context, in state-of-the-art Embedded Multi-DieInterconnection Bridge (EMIB) technology, cross layer leakage is onlydetected at Sort or not detected at all until post assembly test/failureanalysis (FA) if a Sort card is unavailable. In addition, withoutdetailed FA, the failing interfaces are difficult to determine.Embodiments of the present invention can be implemented to provideadditional coverage and also monitor the leakage inline in Fab aftereach process operation. Such an approach can enable early detection androot cause identification of any underlying issues, lending to improvingoverall yield. That is, monitoring in-line during silicon bridgefabrication provides the ability to monitor wafer quality well beforeSort and FA. Testing for defects in silicon bridge manufacturing isimplemented using in-line E-test tools in fab as opposed to testingafter fab processes are completed. Also, fine pitches of sophisticatedproducts may be more suited for testing in-line. It is to be appreciatedthat state-of-the-art products presently have some E-test pads but notfor detecting failure modes in an active region of a silicon bridge die.

Addressing one or more of the above described issues, embodimentsdescribed herein are directed to fabricating testable E-test pads nearthe scribe area. Signals and ground planes from the active die can berouted and tested without compromising overall quality of the silicon.In an embodiment, regardless of the specific implementations describedbelow, a staggered guard ring is used to allow test signal routing topass through a guard ring structure. In an embodiment, also regardlessof the specific implementations described below, guard ring designsdescribed herein are referred to as dual guard ring structures sincethey include at least an inner guard ring and an outer guard ring at anoutermost perimeter of the silicon bride dies, i.e., near the scriberegion.

Providing a high level overview of the concepts described herein, FIG.1A illustrates a cross-sectional view of a semiconductor package havingan Embedded Multi-Die Interconnection Bridge (EMIB) connecting two dies,in accordance with an embodiment of the present invention. Referring toFIG. 1A, a semiconductor package 100 includes a first die 102 (e.g., amemory die) and a second die 104 (e.g., a logic, CPU or SoC die). Thefirst die 102 and second die 104 are coupled to a silicon bridge 106through bumps 108A and 110A of the first die 102 and second die 104,respectively, and bond pads 112A and 112B (also referred to asconductive pads 112A and 112B) of the silicon bridge 106, e.g., bythermal compression bonding (TCB).

The first die 102 and second die 104 are disposed on a package substrate114. The package substrate 114 includes metallization layers 116 (e.g.,vertical arrangement of lines and vias) formed in insulating layers 118.The metallization layers 116 layers may be simple or complex and may befor coupling to other packages or may form part or all of an organicpackage or printed circuit board (PCB), etc. The first die 102 andsecond die 104 may each be coupled directly to the package substrate 114through bumps 108B and 110B, respectively, as is depicted in FIG. 1A.FIG. 1B illustrates a plan view showing the bump arrays 108A, 108B, 110Aand 110B of the first 102 and second 104 dies of FIG. 1A.

Referring again to FIG. 1A, the silicon bridge 106 as depicted isreferred to as an Embedded Multi-Die Interconnection Bridge (EMIB) sinceit is included with the layers of the package substrate 114. In anotherembodiment, such a silicon bridge 106 is not embedded in the package,but rather in an open cavity of a substrate or board. In either case, inan embodiment, and as will be described in greater detail below, thesilicon bridge 106 includes a silicon substrate having an insulatinglayer disposed thereon, the silicon substrate having a perimeter 118. Ametallization structure is disposed on the insulating layer. Themetallization structure includes conductive routing disposed in adielectric material stack. The silicon bridge 106 also includes an innermetal guard ring disposed in the dielectric material stack andsurrounding the conductive routing. An outer metal guard ring of thesilicon bridge 106 is disposed in the dielectric material stack andsurrounds the first metal guard ring. Test pads for signal lines and forVSS lines are included and are surrounded by at least the outer metalguard ring. In an embodiment, the silicon bridge 106 further includes ametal-free region 120 of the dielectric material stack. The metal-freeregion 120 surrounds the outer metal guard ring and is disposed adjacentto the outer metal guard ring and adjacent to the perimeter 118 of thesubstrate of the silicon bridge 106.

As described in greater detail below in association with FIG. 4, in oneembodiment, the inner metal guard ring of the silicon bridge 106 is afirst metal guard ring disposed in the dielectric material stack andsurrounding the conductive routing. The first metal guard ring has aplurality of individual guard ring segments. The outer guard ring of thesilicon bridge 106 is a second metal guard ring disposed in thedielectric material stack and surrounding the first metal guard ring.The test pads of the silicon bridge 106 are disposed between the firstmetal guard ring and the second metal guard ring. Additionally, the testpads are coupled to the conductive routing of the silicon bridge 106 bymetal lines passing through the first metal guard ring.

As described in greater detail below in association with FIG. 5, inanother embodiment, the inner metal guard ring of the silicon bridge 106is a first continuous metal guard ring disposed in the dielectricmaterial stack and surrounding the conductive routing. The outer guardring of the silicon bridge 106 is a second continuous metal guard ringdisposed in the dielectric material stack. The outer guard ringsurrounds a first portion the first continuous metal guard ring at afirst distance from the first continuous metal guard ring. The outerguard ring also surrounds a second portion of the first continuous metalguard ring at a second distance smaller than the first distance. Thetest pads of the silicon bridge 106 are disposed between the secondportion of the first continuous metal guard ring and the metallizationstructure, the test pads coupled to the conductive routing.

Referring again to FIG. 1A, the first 102 and second 104 adjacentsemiconductor dies are disposed on the semiconductor package substrate114 and electrically coupled to one another by the conductive routing ofthe metallization structure of the silicon bridge 106. In oneembodiment, the first semiconductor die 102 is a memory die, and thesecond semiconductor die 104 is a logic die. The first semiconductor die102 is attached to the first plurality of conductive pads 112A of thesilicon bridge 106, and the second semiconductor die 104 is attached tothe second plurality of conductive pads 112B of the silicon bridge 106.In one embodiment, the conductive routing of the silicon bridge 106electrically couples the first plurality of conductive pads 112A withthe second plurality of conductive pads 112B.

As described above, a plurality of silicon bridge dies may be fabricatedon a common silicon wafer which ultimately requires dicing to providesingulated silicon bridge dies. As an example, FIG. 2 illustrates a planview of a portion of a silicon wafer having a plurality of siliconbridge dies fabricated thereon, in accordance with an embodiment of thepresent invention.

Referring to FIG. 2, a portion 200 of a silicon wafer includes a firstsilicon bridge die 202 and a second silicon bridge die 204 thereon. Afirst metal guard ring 206 or 208 surrounds an active region 210 or 212of the first 202 and second 204 silicon bridge dies, respectively. Asecond metal guard ring 214 or 216 surrounds the first metal guard ring206 or 208, respectively. A region 218 or 220 for various metallizationfeatures such as electrical testing (E-test) features is housed includedat least within the second guard ring 214 or 216, respectively, as willbe described in greater detail below. A metal-free scribe line 222separates the first 202 and second 204 silicon bridge dies, outside thesecond guard rings 214 or 216, respectively. It is noted that in FIG. 2,only two silicon bridge dies are depicted. However, it is to beappreciated that a wafer or reticle can include a greater number ofsilicon bridge dies depending upon the wafer or reticle size anddepending on the die size.

In an embodiment, the active die region 210 or 212 of FIG. 2 includesall of the signal and power/ground interconnects, allowing metal-freescribe line 222 in the dicing streets between dies. As a more detailedexample, FIG. 3 illustrates a magnified layout for a dual guard ringdesign of FIG. 2 highlighting test structures fabricated within dualguard ring structure, in accordance with an embodiment of the presentinvention.

Referring to FIG. 3, a portion 300 of a silicon bridge die includes aninner guard ring 302 and an outer guard ring 304. A region 306 betweenguard rings 302 and 304 is used to place all the fab alignment/metrology308 and E-test/EM structures 310. For example, region 308 represents aspace used for fab alignment marks, E-test pads, die preparation modulealignment marks, and metal dummification. Region 310 represents a spaceused of all test structures tested using E-test pads that are used forprocess monitoring, such as in-line process monitoring.

Referring again to FIG. 3, an active area 312 of the silicon bride die300 is included within the inner guard ring 302. A scribe area 314(which may be a metal free zone) is included outside the outer guardring 304. In an embodiment, the E-test/EM structures are entirelycontained within region 306 and they do not cross over to the activeregion 312. Such as dual guard ring 302/304 may based on a metal 1/via1/metal 2/via 2/metal 3/via 3/metal 4 (M1/V1/M2/V2/M3/V3/M4), as isdescribed in greater detail below in association with FIGS. 9 and 10.

Referring again to FIG. 3, in an embodiment, such a dual guard ringframe design 302/304 enables a saw-only die singulation process forsilicon bridge technology. The metal-free scribe line 314 width issuitable to permit a saw blade to cut silicon and dielectric layers(such as silicon oxide layers) without contacting copper (Cu) metalfeatures. In an embodiment, the inner metal guard ring 302 and the outermetal guard ring 304 provide a hermetic seal for electrical routingincluded in active area 312 of the silicon bridge die 300. The innermetal guard ring 302 and outer metal guard ring 304 design may alsoprevent cracks initiated in the scribe area 314 from propagating intothe active area 312 of the silicon bridge die 300.

In accordance with one or more embodiments of the present invention, twospecific implementations of a dual guard ring design enabling in-linetesting of silicon bridge dies are described below. Such implementationsenable E-test pads that can test cross layer leakage across structuresin the active die regions of silicon bridge dies during theirfabrication.

In a first embodiment, the inner guard ring (i.e., the guard ringclosest to the active die region of the silicon bridge die) is brokenup. Structures of interest are routed to selected E-test pads. Inaddition, a second row of discontinuous metal/via trenches is includedin a staggered configuration to compensate for the broken inner guardring. This approach increases the length across which a crack mustpropagate before it can enter the active region. Depending on whichlayers are routed to the E-test pads, test leakage across such layerscan be selectively tested inline. For example, FIG. 4 illustrates afirst implementation of a dual guard ring design enabling in-linetesting of silicon bridge dies, in accordance with an embodiment of thepresent invention.

Referring to FIG. 4, a dual guard ring structure 400 is based on astaggered inner guard-ring with E-test pad routing where the inner guardring is broken up, staggered, and signal/VSS from different layers isrouted to test pads for leakage tests. The dual guard ring structure 400includes an outer guard ring 402, an inner guard ring 404, and a region406 between the outer guard ring 402 and the inner guard ring 404. Ascribe area 408 (which may be a metal free zone) is outside the outerguard ring 402. An active area 410 is inside the inner guard ring 404.

In an embodiment, inner guard ring 404 includes a plurality ofindividual guard ring segments. For example, in one embodiment, innerguard ring 404 includes two lines 412 and 414 of staggered guard ringportions 416. This arrangement may be referred to as a plurality ofindividual guard ring segments of the inner metal guard ring 404arranged in two adjacent lines of staggered individual guard ringsegments. In an exemplary implementation, a signal 1 test pad 418 isincluded between the inner guard ring 404 and the outer guard ring 402,with a line 420 connecting the pad 418 to the active area 410 throughthe two lines 412 and 414 of staggered guard ring portions 416 of innerguard ring 404. A signal 2 test pad 422 is included between the innerguard ring 404 and the outer guard ring 402, with a line 424 connectingthe pad 422 to the active area 410 through the two lines 412 and 414 ofstaggered guard ring portions 416 of inner guard ring 404. A signal 3test pad 426 is included between the inner guard ring 404 and the outerguard ring 402, with a line 428 connecting the pad 426 to the activearea 410 through the two lines 412 and 414 of staggered guard ringportions 416 of inner guard ring 404. A VSS test pad 430 is includedbetween the inner guard ring 404 and the outer guard ring 402, with aline 432 connecting the pad 430 to the active area 410 through the twolines 412 and 414 of staggered guard ring portions 416 of inner guardring 404.

In an embodiment, the scribe area 408 is a metal-free region of thedielectric material stack surrounding the outer metal guard ring 402.The metal-free region 408 is disposed adjacent to the outer metal guardring 402 and adjacent to the perimeter of the substrate of the siliconbridge die. In one embodiment, the outer metal guard ring 402 provides ahermetic seal for the metallization structure of the active area 410. Inone embodiment, the substrate is free from having semiconductor devicesdisposed therein. In one embodiment, the substrate is a singlecrystalline silicon substrate.

In a second embodiment, instead of breaking the inner guard ring, aportion of the inner guard ring is looped back behind the E-test pads,to provide a “continuous” dual guard-ring design as compared with thedesign of FIG. 4 which is based on a broken up inner guard ring. As anexample, FIG. 5 illustrates a second implementation of a dual guard ringdesign enabling in-line testing of silicon bridge dies, in accordancewith an embodiment of the present invention.

Referring to FIG. 5, a dual guard ring structure 500 is based on a“looped back” inner guard ring where the inner guard ring is both brokenup and wrapped around the test pads, e.g., to improve hermetic sealing,and the signal/VSS from different layers can be routed to test pads forleakage tests. The dual guard ring structure 500 includes an outer guardring 502, an inner guard ring 504. The inner guard ring 504 may bedescribed as a first continuous metal guard ring with a portion 511 thatis between a region 506 and an active region 510. However, to maintaincontinuity, the inner guard ring 504 loops behind the region 506 atlocations where certain in-line test features are located. The outerguard ring may be described as a second continuous metal guard ring thatsurrounds a first portion (at location 511) of the first continuousmetal guard ring 504 at a first distance from the first continuous metalguard ring 504. The outer guard ring 502 surrounds a second portion(portion looped back around region 506) of the first continuous metalguard ring at a second distance smaller than the first distance. Ascribe area 508 (which may be a metal free zone) is outside the outerguard ring 502. An active area 510 is inside the inner guard ring 504.

In one embodiment, electrical testing features are disposed between thesecond portion of the first continuous metal guard ring 504 and aplurality of individual guard ring segments 516 arranged in two adjacentlines 512 and 514 of staggered individual guard ring segments 516 (i.e.,the electrical testing features are disposed in region 506. In anexemplary implementation, a signal 1 test pad 518 is included in region506, with a line 520 connecting the pad 518 to the active area 510through the two lines 512 and 514 of staggered guard ring portions 516.A signal 2 test pad 522 is included in region 506, with a line 524connecting the pad 522 to the active area 510 through the two lines 512and 514 of staggered guard ring portions 516. A signal 3 test pad 526 isincluded in region 506, with a line 528 connecting the pad 526 to theactive area 510 through the two lines 512 and 514 of staggered guardring portions 516 of inner guard ring 504. A VSS test pad 530 isincluded in region 506, with a line 532 connecting the pad 530 to theactive area 510 through the two lines 512 and 514 of staggered guardring portions 516.

In an embodiment, the scribe area 508 is a metal-free region of thedielectric material stack surrounding the outer metal guard ring 502.The metal-free region 508 is disposed adjacent to the outer metal guardring 502 and adjacent to the perimeter of the substrate of the siliconbridge die. In one embodiment, one or both of the inner guard ring 504and the outer metal guard ring 502 provides a hermetic seal for themetallization structure of the active area 510. In one embodiment, thesubstrate is free from having semiconductor devices disposed therein. Inone embodiment, the substrate is a single crystalline silicon substrate.

In accordance with an embodiment of the present invention, a dual guardring design enabling in-line testing of silicon bridge dies will retaina region where e-test structures exist post saw cut (singulation). Thatis, singulation does not destroy the dual guard ring region. As anexample, FIG. 6 illustrates a plan view of a portion of a silicon waferfrom FIG. 2 highlighting artifacts of implementations described herein,in accordance with an embodiment of the present invention.

Referring to FIG. 6, a portion 200 of a silicon wafer includes a firstsilicon bridge die 202 and a second silicon bridge die 204 thereon. Afirst metal guard ring 206 or 208 surrounds an active region 210 or 212of the first 202 and second 204 silicon bridge dies, respectively. Asecond metal guard ring 214 or 216 surrounds the first metal guard ring206 or 208, respectively. A region 218 or 220 for various metallizationfeatures such as electrical testing (E-test) features is housed includedat least within the second guard ring 214 or 216, respectively, as willbe described in greater detail below. A metal-free scribe line 222separates the first 202 and second 204 silicon bridge dies, outside thesecond guard rings 214 or 216, respectively. The E-test pads areincluded entirely within dual guard ring structure. Accordingly, asingulation process involving a saw blade cutting through the metal freezone 222 leaves the region between the dual guard ring structure intact.The resulting singulated dies include such E-test pads within the dualguard ring structure post saw cut.

FIG. 7 illustrates a cross-sectional view of a possible E-test routinglayout 700 for a silicon bridge die, in accordance with an embodiment ofthe present invention. In the exemplary layout 700, a metallizationregion 702 utilizes metal 1 and metal 3 (M1/M3) for VSS ground routing.The metallization region 702 further utilizes metal 2 and metal 4(M2/M4) for signal routing.

FIG. 8 is a schematic layout of an E-test spline 800 for a siliconbridge die, in accordance with an embodiment of the present invention.In the exemplary spline 800, each E-test Spline has 40 E-test pads withdimensions of 41.68 micron×49 micron pad size, a pad pitch of 55.68micron (based on 14 micron spacing). The cell size is 2253.2 micron×55micron. In an embodiment, cell placement is horizontal (based on wafernotch down orientation).

It is to be appreciated that a dual guard ring structure may befabricated from a plurality of layers of a metallization structure, suchas from a plurality of alternating metal lines and vias. As an example,FIG. 9 illustrates a cross-sectional view of a guard ring of a dualguard ring structure, in accordance with an embodiment of the presentinvention. FIG. 10 illustrates a cross-sectional view of a dual guardring structure, in accordance with an embodiment of the presentinvention.

Referring to FIGS. 9 and 10 collectively, in an embodiment, asemiconductor structure 900 (such as a silicon bridge) includes asubstrate 902 having an insulating layer disposed thereon 904. Thesubstrate has a perimeter 906, an outer most portion of which isdepicted on the right-hand side of FIG. 10. A metallization structure908 is disposed on the insulating layer 904. The metallization structure908 includes conductive routing 910 disposed in a dielectric materialstack 912.

A first metal guard ring 914 is disposed in the dielectric materialstack 912 and surrounds the conductive routing 910. A second metal guardring 916 (only shown in FIG. 10) is disposed in the dielectric materialstack 912 and surrounds the first metal guard ring 914. A metal-freeregion 918 of the dielectric material stack 912 surrounds the secondmetal guard ring 916 (only shown in FIG. 10). The metal-free region 918is disposed adjacent to the second metal guard ring 916 and adjacent tothe perimeter 906 of the substrate 902.

In an embodiment, at least one of the first metal guard ring 914 or thesecond metal guard ring 916 includes a vertical stack of alternatingmetal lines and vias aligned along a common axis 999, as is depicted inFIG. 9. In one embodiment, an uppermost layer of the metallizationstructure includes first and second pluralities of conductive padsthereon, such as pad 922 shown in FIG. 9 (although it is to beappreciated that the pad may be omitted from the guard ring structureeven if included in the metallization of the active die region). In onesuch embodiment, the conductive routing electrically couples a firstplurality of conductive pads with a second plurality of conductive padsof the silicon bridge. In one embodiment, the first and secondpluralities of conductive pads include a layer of copper having athickness of greater than approximately 5 microns.

In one embodiment, the semiconductor structure includes metal features919 disposed in the dielectric material stack, between the first metalguard ring 914 and the second metal guard ring 916. Additionally, anE-test pad 920 may be included between the first metal guard ring 914and the second metal guard ring 916, as is depicted in FIG. 10. In anembodiment, the substrate 902 is free from having semiconductor devicesdisposed therein. That is, the primary function of the silicon bridgedie is to provide local and direct communication between two diescoupled to the silicon bridge die. In one embodiment, the substrate is asingle crystalline silicon substrate.

Although the above describe embodiments are directed to two individualdies coupled to one another by a silicon bridge or EMIB, it is to beappreciated that complex structure may also benefit from embodimentsdescribed herein. In a first example, FIG. 11 illustrates across-sectional view of a semiconductor package including multiple diecoupled with an Embedded Multi-Die Interconnection Bridge (EMIB), inaccordance with an embodiment of the present invention. Referring toFIG. 11, the semiconductor package 1100 includes a first die 1152 (suchas a logic die central processing unit, CPU) and a memory die stack1154. The first die 1152 and the memory die stack 1154 are coupled to anEMIB 1156 through bumps 1158 and 1160 of the first die 1152 and thememory die stack 1154, respectively, e.g., by thermal compressionbonding (TCB). The EMIB 1156 is embedded in a substrate (e.g., aflexible organic substrate) or board (such as an epoxy PCB material)material 1170. An underfill material 1199 may be included between thefirst die 1152 and the EMIB 1156/substrate 1170 interface and betweenthe memory die stack 1154 and the EMIB 1156/substrate 1170 interface, asis depicted in FIG. 11. In an embodiment, the EMIB 1156 includes a dualmetal guard ring surrounded by a metal free portion outside of theoutermost metal guard ring with electrical testing features housedwithin the outermost metal guard ring, as described above.

In a second example, FIG. 12 illustrates a plan view of a package layoutfor co-packaged high performance computing (HPC) die and high bandwidthmemory (HBM) layout, in accordance with an embodiment of the presentinvention. Referring to FIG. 12, a package layout 1200 includes a commonsubstrate 1202. A central processing unit or system-on-chip (CPU/SoC)die 1204 is supported by the substrate 1202 along with eight memory dies1206. A plurality of EMIBs 1208 bridge the memory dies 1206 to theCPU/SoC die 1204 by C4 connections 1210. The die-to-die spacing 1212 isapproximately 100-200 microns. It is to be appreciated that, from atop-down view perspective, the dies 1204 and 1206 are disposed above theC4 connections 1210, which are disposed above the EMIBs 1208, which areincluded in the substrate 1202. In an embodiment, one or more of theEMIBs 1208 includes a dual metal guard ring surrounded by a metal freeportion outside of the outermost metal guard ring, with electricaltesting features housed within the outermost metal guard ring, asdescribed above.

As described above, in an embodiment, a substrate for a silicon bridgemay be a single crystalline silicon substrate. In other embodiments, andstill in the context of a “silicon bridge,” the substrate may becomposed of a multi- or single-crystal of a material which may include,but is not limited to, germanium, silicon-germanium or a Group III-Vcompound semiconductor material. In another embodiment, a glasssubstrate is used.

Referencing the above description regarding silicon bridge technology,in an embodiment, an insulating, dielectric or interlayer dielectric(ILD) material is one such as, but not limited to, oxides of silicon(e.g., silicon dioxide (SiO₂)), doped oxides of silicon, fluorinatedoxides of silicon, carbon doped oxides of silicon, various low-kdielectric materials known in the arts, and combinations thereof. Theinsulating, dielectric or interlayer dielectric (ILD) material may beformed by conventional techniques, such as, for example, chemical vapordeposition (CVD), physical vapor deposition (PVD), or by otherdeposition methods.

Referencing the above description regarding silicon bridge technology,in an embodiment, interconnect or conductive routing material iscomposed of one or more metal or other conductive structures. A commonexample is the use of copper lines and structures (such as vias) thatmay or may not include barrier layers between the copper and surroundingILD material. As used herein, the term metal includes alloys, stacks,and other combinations of multiple metals. For example, the metalinterconnect lines may include barrier layers, stacks of differentmetals or alloys, etc. The interconnect lines or conductive routing arealso sometimes referred to in the arts as traces, wires, lines, metal,or simply interconnects. The dual metal guard ring designs describedabove may be fabricated from the same materials as the metallizationstructure and conductive routing.

In accordance with one or more embodiments described herein, a framedesign for a wafer of silicon bridges dies includes, for each individualdie, a first (outer) guard ring in close proximity to a saw cut area,providing initial protection during dicing. A second (inner) guard ringis located around the die edge. One or more cracks that propagatethrough the outer guard ring during (or after) a singulation process maybe terminated between the inner and outer guard rings.

As described above, a plurality of silicon bridge dies may be fabricatedfrom a common wafer. A method of fabricating a plurality of siliconbridge dies includes providing a wafer having a plurality of siliconbridge dies thereon. Each of the plurality of silicon bridge dies isseparated from one another by metal-free scribe lines. The method offabricating the plurality of silicon bridge dies includes singulatingthe plurality of silicon bridge dies by sawing the metal-free scribelines of the wafer. In accordance with an embodiment of the presentinvention, each of the plurality of silicon bridge dies is protected bythe dual metal guard ring during the sawing. In an embodiment, prior tothe sawing, at an earlier stage in fabrication, the silicon bridge diescan be E-tested using test structures included within a dual guard ringstructure.

In one embodiment, singulating the plurality of silicon bridge diesinvolves leaving a portion of the metal-free scribe lines to remain as aportion of each of the singulated plurality of silicon bridge dies. Inone embodiment, at least one of the metal guard rings of the dual metalguard ring provides a hermetic seal for each of the plurality of siliconbridge dies during the sawing. In one embodiment, a crack is formedduring the sawing the metal-free scribe lines of the wafer. In aparticular embodiment, the crack propagates through an outermost metalguard ring of the dual metal guard ring but not through an inner mostmetal guard ring of the dual metal guard ring, even subsequent to thesawing process. This, in an embodiment, a dual metal guard ring designhaving a metal-free outermost region enables a saw-only die singulationprocess for silicon bridge technologies.

Embodiments describe above, upon implementation in a silicon bridge diefabrication process, can provide a more robust in-line method ofdetecting cross-layer leakage prior to assembly builds. A key benefit ofembodiments described herein is to improve the overall yield of the EMIBsilicon process by capturing cross-layer leakage defects in-line in fabso that substrate vendors and/or customers receive known good die.

FIG. 13 is a schematic of a computer system 1300, in accordance with anembodiment of the present invention. The computer system 1300 (alsoreferred to as the electronic system 1300) as depicted can embody asilicon bridge having a dual guard ring design, according to any of theseveral disclosed embodiments and their equivalents as set forth in thisdisclosure. The computer system 1300 may be a mobile device such as anetbook computer. The computer system 1300 may be a mobile device suchas a wireless smart phone. The computer system 1300 may be a desktopcomputer. The computer system 1300 may be a hand-held reader. Thecomputer system 1300 may be a server system. The computer system 1300may be a supercomputer or high-performance computing system.

In an embodiment, the electronic system 1300 is a computer system thatincludes a system bus 1320 to electrically couple the various componentsof the electronic system 1300. The system bus 1320 is a single bus orany combination of busses according to various embodiments. Theelectronic system 1300 includes a voltage source 1330 that providespower to the integrated circuit 1310. In some embodiments, the voltagesource 1330 supplies current to the integrated circuit 1310 through thesystem bus 1320.

The integrated circuit 1310 is electrically coupled to the system bus1320 and includes any circuit, or combination of circuits according toan embodiment. In an embodiment, the integrated circuit 1310 includes aprocessor 1312 that can be of any type. As used herein, the processor1312 may mean any type of circuit such as, but not limited to, amicroprocessor, a microcontroller, a graphics processor, a digitalsignal processor, or another processor. In an embodiment, the processor1312 includes, or is coupled with, a silicon bridge having a dual guardring design, as disclosed herein. In an embodiment, SRAM embodiments arefound in memory caches of the processor. Other types of circuits thatcan be included in the integrated circuit 1310 are a custom circuit oran application-specific integrated circuit (ASIC), such as acommunications circuit 1314 for use in wireless devices such as cellulartelephones, smart phones, pagers, portable computers, two-way radios,and similar electronic systems, or a communications circuit for servers.In an embodiment, the integrated circuit 1310 includes on-die memory1316 such as static random-access memory (SRAM). In an embodiment, theintegrated circuit 1310 includes embedded on-die memory 1316 such asembedded dynamic random-access memory (eDRAM).

In an embodiment, the integrated circuit 1310 is complemented with asubsequent integrated circuit 1311. Useful embodiments include a dualprocessor 1313 and a dual communications circuit 1315 and dual on-diememory 1317 such as SRAM. In an embodiment, the dual integrated circuit1310 includes embedded on-die memory 1317 such as eDRAM.

In an embodiment, the electronic system 1300 also includes an externalmemory 1340 that in turn may include one or more memory elementssuitable to the particular application, such as a main memory 1342 inthe form of RAM, one or more hard drives 1344, and/or one or more drivesthat handle removable media 1346, such as diskettes, compact disks(CDs), digital variable disks (DVDs), flash memory drives, and otherremovable media known in the art. The external memory 1340 may also beembedded memory 1348 such as the first die in a die stack, according toan embodiment.

In an embodiment, the electronic system 1300 also includes a displaydevice 1350, an audio output 1360. In an embodiment, the electronicsystem 1300 includes an input device such as a controller 1370 that maybe a keyboard, mouse, trackball, game controller, microphone,voice-recognition device, or any other input device that inputsinformation into the electronic system 1300. In an embodiment, an inputdevice 1370 is a camera. In an embodiment, an input device 1370 is adigital sound recorder. In an embodiment, an input device 1370 is acamera and a digital sound recorder.

As shown herein, the integrated circuit 1310 can be implemented in anumber of different embodiments, including a package substrate having asilicon bridge having a dual guard ring design, according to any of theseveral disclosed embodiments and their equivalents, an electronicsystem, a computer system, one or more methods of fabricating anintegrated circuit, and one or more methods of fabricating an electronicassembly that includes a package substrate having a silicon bridgehaving a dual guard ring design, according to any of the severaldisclosed embodiments as set forth herein in the various embodiments andtheir art-recognized equivalents. The elements, materials, geometries,dimensions, and sequence of operations can all be varied to suitparticular I/O coupling requirements including array contact count,array contact configuration for a microelectronic die embedded in aprocessor mounting substrate according to any of the several disclosedpackage substrates having a silicon bridge having a dual guard ringdesign embodiments and their equivalents. A foundation substrate may beincluded, as represented by the dashed line of FIG. 13. Passive devicesmay also be included, as is also depicted in FIG. 13.

Embodiments of the present invention include guard ring designs enablingin-line testing of silicon bridges for semiconductor packages, and theresulting silicon bridges and semiconductor packages.

In an embodiment, a semiconductor structure includes a substrate havingan insulating layer disposed thereon. A metallization structure isdisposed on the insulating layer. The metallization structure incudesconductive routing disposed in a dielectric material stack. Thesemiconductor structure also includes a first metal guard ring disposedin the dielectric material stack and surrounding the conductive routing.The first metal guard ring includes a plurality of individual guard ringsegments. The semiconductor structure also includes a second metal guardring disposed in the dielectric material stack and surrounding the firstmetal guard ring. Electrical testing features are disposed in thedielectric material stack, between the first metal guard ring and thesecond metal guard ring. The electrical testing features are coupled tothe conductive routing by metal lines passing through the first metalguard ring.

In one embodiment, the electrical testing features include test pads forsignal lines and for VSS lines.

In one embodiment, the plurality of individual guard ring segments ofthe first metal guard ring is arranged in two adjacent lines ofstaggered individual guard ring segments.

In one embodiment, the substrate has a perimeter, and the semiconductorstructure further includes a metal-free region of the dielectricmaterial stack surrounding the second metal guard ring. The metal-freeregion is disposed adjacent to the second metal guard ring and adjacentto the perimeter of the substrate.

In one embodiment, the second metal guard ring provides a hermetic sealfor the metallization structure.

In one embodiment, at least one of the first metal guard ring or thesecond metal guard ring comprises a vertical stack of alternating metallines and vias aligned along a common axis.

In one embodiment, an uppermost layer of the metallization structurecomprises first and second pluralities of conductive pads thereon.

In one embodiment, the conductive routing electrically couples the firstplurality of conductive pads with the second plurality of conductivepads.

In one embodiment, the substrate is free from having semiconductordevices disposed therein.

In one embodiment, the substrate is a single crystalline siliconsubstrate.

In an embodiment, a semiconductor structure includes a substrate havingan insulating layer disposed thereon. A metallization structure isdisposed on the insulating layer, the metallization structure includingconductive routing disposed in a dielectric material stack. A firstcontinuous metal guard ring is disposed in the dielectric material stackand surrounds the conductive routing. A second continuous metal guardring is disposed in the dielectric material stack and surrounds a firstportion the first continuous metal guard ring at a first distance fromthe first continuous metal guard ring, and surrounds a second portion ofthe first continuous metal guard ring at a second distance smaller thanthe first distance. Electrical testing features are disposed in thedielectric material stack, between the second portion of the firstcontinuous metal guard ring and the metallization structure, theelectrical testing features coupled to the conductive routing.

In one embodiment, the electrical testing features includes test padsfor signal lines and for VSS lines.

In one embodiment, the electrical testing features are disposed betweenthe second portion of the first continuous metal guard ring and aplurality of individual guard ring segments arranged in two adjacentlines of staggered individual guard ring segments, and the electricaltesting features are coupled to the conductive routing by metal linespassing through the plurality of individual guard ring segments.

In one embodiment, the substrate has a perimeter, and the semiconductorstructure further includes a metal-free region of the dielectricmaterial stack surrounding the second continuous metal guard ring, themetal-free region disposed adjacent to the second continuous metal guardring and adjacent to the perimeter of the substrate.

In one embodiment, one or both of the first continuous metal guard ringand the second continuous metal guard ring provides a hermetic seal forthe metallization structure.

In one embodiment, at least one of the first metal guard ring or thesecond metal guard ring includes a vertical stack of alternating metallines and vias aligned along a common axis.

In one embodiment, an uppermost layer of the metallization structureincludes first and second pluralities of conductive pads thereon.

In one embodiment, the conductive routing electrically couples the firstplurality of conductive pads with the second plurality of conductivepads.

In one embodiment, the substrate is free from having semiconductordevices disposed therein.

In one embodiment, the substrate is a single crystalline siliconsubstrate.

In an embodiment, a semiconductor package includes an Embedded Multi-DieInterconnection Bridge (EMIB) including a silicon bridge disposed withina semiconductor package substrate. The silicon bridge includes a siliconsubstrate having an insulating layer disposed thereon. The siliconbridge also includes a metallization structure disposed on theinsulating layer, the metallization structure including conductiverouting disposed in a dielectric material stack. The silicon bridge alsoincludes an inner metal guard ring disposed in the dielectric materialstack and surrounding the conductive routing. The silicon bridge alsoincludes an outer metal guard ring disposed in the dielectric materialstack and surrounding the first metal guard ring; and test pads forsignal lines and for VSS lines, the test pads surrounded by at least theouter metal guard ring. The semiconductor structure also includes firstand second adjacent semiconductor dies disposed on the semiconductorpackage substrate and electrically coupled to one another by theconductive routing of the metallization structure of the silicon bridge.

In one embodiment, the first semiconductor die is a memory die, and thesecond semiconductor die is a logic die.

In one embodiment, the inner metal guard ring of the silicon bridge is afirst metal guard ring disposed in the dielectric material stack andsurrounding the conductive routing, the first metal guard ring having aplurality of individual guard ring segments, where the outer guard ringof the silicon bridge is a second metal guard ring disposed in thedielectric material stack and surrounding the first metal guard ring,and where the test pads of the silicon bridge are disposed between thefirst metal guard ring and the second metal guard ring, the test padscoupled to the conductive routing by metal lines passing through thefirst metal guard ring.

In one embodiment, the inner metal guard ring of the silicon bridge is afirst continuous metal guard ring disposed in the dielectric materialstack and surrounding the conductive routing, where the outer guard ringof the silicon bridge is a second continuous metal guard ring disposedin the dielectric material stack and surrounding a first portion thefirst continuous metal guard ring at a first distance from the firstcontinuous metal guard ring, and surrounding a second portion of thefirst continuous metal guard ring at a second distance smaller than thefirst distance, and where the test pads of the silicon bridge aredisposed between the second portion of the first continuous metal guardring and the metallization structure, the test pads coupled to theconductive routing.

In one embodiment, the substrate of the silicon bridge has a perimeter,and the silicon bridge further includes a metal-free region of thedielectric material stack surrounding the outer metal guard ring, wherethe metal-free region is disposed adjacent to the outer metal guard ringand adjacent to the perimeter of the substrate.

What is claimed is:
 1. A semiconductor structure, comprising: asubstrate having an insulating layer disposed thereon; a metallizationstructure disposed on the insulating layer, the metallization structurecomprising conductive routing disposed in a dielectric material stack,wherein an uppermost layer of the metallization structure comprisesfirst and second pluralities of conductive pads thereon; a first metalguard ring disposed in the dielectric material stack and surrounding theconductive routing, the first metal guard ring comprising a plurality ofindividual guard ring segments; a second metal guard ring disposed inthe dielectric material stack and surrounding the first metal guardring, the second metal guard ring continuous around the first metalguard ring; and electrical testing features disposed in the dielectricmaterial stack, between the first metal guard ring and the second metalguard ring, the electrical testing features coupled to the conductiverouting by metal lines passing through the first metal guard ring. 2.The semiconductor structure of claim 1, wherein the electrical testingfeatures comprises test pads for signal lines and for VSS lines.
 3. Thesemiconductor structure of claim 1, wherein the plurality of individualguard ring segments of the first metal guard ring is arranged in twoadjacent lines of staggered individual guard ring segments.
 4. Thesemiconductor structure of claim 1, wherein the substrate has aperimeter, the semiconductor structure further comprising a metal-freeregion of the dielectric material stack surrounding the second metalguard ring, the metal-free region disposed adjacent to the second metalguard ring and adjacent to the perimeter of the substrate.
 5. Thesemiconductor structure of claim 1, wherein the second metal guard ringprovides a hermetic seal for the metallization structure.
 6. Thesemiconductor device of claim 1, wherein at least one of the first metalguard ring or the second metal guard ring comprises a vertical stack ofalternating metal lines and vias aligned along a common axis.
 7. Thesemiconductor structure of claim 1, wherein the conductive routingelectrically couples the first plurality of conductive pads with thesecond plurality of conductive pads.
 8. The semiconductor structure ofclaim 1, wherein the substrate is free from having semiconductor devicesdisposed therein.
 9. The semiconductor structure if claim 1, wherein thesubstrate is a single crystalline silicon substrate.
 10. A semiconductorstructure, comprising: a substrate having an insulating layer disposedthereon; a metallization structure disposed on the insulating layer, themetallization structure comprising conductive routing disposed in adielectric material stack, wherein an uppermost layer of themetallization structure comprises first and second pluralities ofconductive pads thereon; a first continuous metal guard ring disposed inthe dielectric material stack and surrounding the conductive routing; asecond continuous metal guard ring disposed in the dielectric materialstack and surrounding a first portion of the first continuous metalguard ring at a first distance from the first continuous metal guardring, and surrounding a second portion of the first continuous metalguard ring at a second distance smaller than the first distance; andelectrical testing features disposed in the dielectric material stack,between the second portion of the first continuous metal guard ring andthe metallization structure, the electrical testing features coupled tothe conductive routing.
 11. The semiconductor structure of claim 10,wherein the electrical testing features comprises test pads for signallines and for VSS lines.
 12. The semiconductor structure of claim 10,wherein the electrical testing features are disposed between the secondportion of the first continuous metal guard ring and a plurality ofindividual guard ring segments arranged in two adjacent lines ofstaggered individual guard ring segments, and wherein the electricaltesting features are coupled to the conductive routing by metal linespassing through the plurality of individual guard ring segments.
 13. Thesemiconductor structure of claim 10, wherein the substrate has aperimeter, the semiconductor structure further comprising a metal-freeregion of the dielectric material stack surrounding the secondcontinuous metal guard ring, the metal-free region disposed adjacent tothe second continuous metal guard ring and adjacent to the perimeter ofthe substrate.
 14. The semiconductor structure of claim 10, wherein oneor both of the first continuous metal guard ring and the secondcontinuous metal guard ring provides a hermetic seal for themetallization structure.
 15. The semiconductor device of claim 10,wherein at least one of the first metal guard ring or the second metalguard ring comprises a vertical stack of alternating metal lines andvias aligned along a common axis.
 16. The semiconductor structure ofclaim 10, wherein the conductive routing electrically couples the firstplurality of conductive pads with the second plurality of conductivepads.
 17. The semiconductor structure of claim 10, wherein the substrateis free from having semiconductor devices disposed therein.
 18. Thesemiconductor structure if claim 10, wherein the substrate is a singlecrystalline silicon substrate.
 19. A semiconductor package, comprising:an embedded multi-die interconnection bridge (EMIB) comprising a siliconbridge disposed within a semiconductor package substrate, the siliconbridge comprising: a silicon substrate having an insulating layerdisposed thereon; a metallization structure disposed on the insulatinglayer, the metallization structure comprising conductive routingdisposed in a dielectric material stack; an inner metal guard ringdisposed in the dielectric material stack and surrounding the conductiverouting; an outer metal guard ring disposed in the dielectric materialstack and surrounding the first metal guard ring; and test pads forsignal lines and for VSS lines, the test pads surrounded by at least theouter metal guard ring; and first and second adjacent semiconductor diesdisposed on the semiconductor package substrate and electrically coupledto one another by the conductive routing of the metallization structureof the silicon bridge.
 20. The semiconductor package of claim 19,wherein the first semiconductor die is a memory die, and the secondsemiconductor die is a logic die.
 21. The semiconductor package of claim19, wherein the inner metal guard ring of the silicon bridge is a firstmetal guard ring disposed in the dielectric material stack andsurrounding the conductive routing, the first metal guard ringcomprising a plurality of individual guard ring segments, wherein theouter guard ring of the silicon bridge is a second metal guard ringdisposed in the dielectric material stack and surrounding the firstmetal guard ring, and wherein the test pads of the silicon bridge aredisposed between the first metal guard ring and the second metal guardring, the test pads coupled to the conductive routing by metal linespassing through the first metal guard ring.
 22. The semiconductorpackage of claim 19, wherein the inner metal guard ring of the siliconbridge is a first continuous metal guard ring disposed in the dielectricmaterial stack and surrounding the conductive routing, wherein the outerguard ring of the silicon bridge is a second continuous metal guard ringdisposed in the dielectric material stack and surrounding a firstportion the first continuous metal guard ring at a first distance fromthe first continuous metal guard ring, and surrounding a second portionof the first continuous metal guard ring at a second distance smallerthan the first distance, and wherein the test pads of the silicon bridgeare disposed between the second portion of the first continuous metalguard ring and the metallization structure, the test pads coupled to theconductive routing.
 23. The semiconductor package of claim 19, whereinthe substrate of the silicon bridge has a perimeter, the silicon bridgefurther comprising a metal-free region of the dielectric material stacksurrounding the outer metal guard ring, wherein the metal-free region isdisposed adjacent to the outer metal guard ring and adjacent to theperimeter of the substrate.
 24. A semiconductor structure, comprising: asubstrate having an insulating layer disposed thereon; a metallizationstructure disposed on the insulating layer, the metallization structurecomprising conductive routing disposed in a dielectric material stack,wherein an uppermost layer of the metallization structure comprisesfirst and second pluralities of conductive pads thereon; a first metalguard ring disposed in the dielectric material stack and surrounding theconductive routing, the first metal guard ring comprising a plurality ofindividual guard ring segments; a second metal guard ring disposed inthe dielectric material stack and surrounding the first metal guardring; and electrical testing features disposed in the dielectricmaterial stack, between the first metal guard ring and the second metalguard ring, the electrical testing features coupled to the conductiverouting by metal lines passing through the first metal guard ring.
 25. Asemiconductor structure, comprising: a substrate having an insulatinglayer disposed thereon, wherein the substrate is free from havingsemiconductor devices disposed therein; a metallization structuredisposed on the insulating layer, the metallization structure comprisingconductive routing disposed in a dielectric material stack; a firstmetal guard ring disposed in the dielectric material stack andsurrounding the conductive routing, the first metal guard ringcomprising a plurality of individual guard ring segments; a second metalguard ring disposed in the dielectric material stack and surrounding thefirst metal guard ring; and electrical testing features disposed in thedielectric material stack, between the first metal guard ring and thesecond metal guard ring, the electrical testing features coupled to theconductive routing by metal lines passing through the first metal guardring.
 26. A semiconductor structure, comprising: a substrate having aninsulating layer disposed thereon, wherein the substrate is free fromhaving semiconductor devices disposed therein; a metallization structuredisposed on the insulating layer, the metallization structure comprisingconductive routing disposed in a dielectric material stack; a firstcontinuous metal guard ring disposed in the dielectric material stackand surrounding the conductive routing; a second continuous metal guardring disposed in the dielectric material stack and surrounding a firstportion of the first continuous metal guard ring at a first distancefrom the first continuous metal guard ring, and surrounding a secondportion of the first continuous metal guard ring at a second distancesmaller than the first distance; and electrical testing featuresdisposed in the dielectric material stack, between the second portion ofthe first continuous metal guard ring and the metallization structure,the electrical testing features coupled to the conductive routing.